In a separate incident, a 1992 letter was sent to the FBI that was marked "extortion," USA Today reported.

In that letter, a female writer demanded $100,000 or she would reveal "certain details" of Houston's "private life."

A subsequent letter which threatened that the writer had "intimate details" of Houston's "romantic relationships" demanded a total of $250,000.

The files detail an interview conducted with Houston at the New Jersey offices of her management company; these files are "heavily redacted," says The Huffington Post.

They do, however, reveal that Houston's father paid off the writer of the letter, the New York Post says; the FBI's investigation concluded that no crime occurred and closed the case.

The FBI did not investigate Houston's 2012 drowning in a Beverly Hills hotel bathroom. The Los Angeles coroner, who autopsied Houston, revealed that the singer had cocaine, marijuana and several prescription medications in her system, yet drowning caused her death.